I suspect that cartoon implies a deep and chilling insight. COVID-19, or HIV, people notice. But does that mean we notice everything? The greatest vulnerability of pathogens is our brains, so wouldn't that mean strong evolutionary pressure to mess with our brains in such a way that we don't notice we're ill? How much of human social evolution is driven by that?
I don't think the molecular tools available to wildlife are sophisticated enough to achieve what you are describing (i.e. messing with higher-ish cognitive functions). This would be like modifying our proprioception but ALSO the perception of others ?
